The automatic dart sewing units of the prior art do have several drawbacks since, during the dart sewing operation, fabrics are held to the working surface by means of a counter clamp while sliding over the surface.
The result is that fabrics are not steadily held during the sewing operation and, consequently, darts often turn out irregular in shape and size.
A further drawback is that the automatic dart sewing units do not carry out the sewing of darts at a distance of 10 to 15 millimeters from a pocket opening in trousers or skirts since, because of their structure, it is not possible to hold fabrics to the plate which carries them under the counter clamp by which, in turn, the fabrics are held to the working surface.
More generically, the units do not allow fabrics to be quickly applied nor to be easily positioned under the needle of the sewing machine.* FNT (*) Document U.S. Pat. No. 5,264,340 refers to a method and apparatus for sewing labels, that solve the problem to easily change the sewing template whenever the type of label to be sewn on the workpiece is changed.